Missiles are typically ejected from a housing or support by means of a mechanical ejector, an expulsion charge or a thrust motor. Missiles of this type frequently use a rotating afterbody, either driven by the rocket exhaust or by aerodynamic fins, in order to achieve improved stability. In order to assure safe operation, it is desirable that the warhead of a missile not be armed until after the missile has separated and traveled a predetermined distance from its housing or support.
Prior art systems for arming sequence initiation are often mechanical in nature and tend to be complex both in structure and operation. Because of this mechanical complexity, reliability of the devices is of concern and a certain number of failures can be expected. Furthermore, the requirement that the missile not arm prior to safe separation means that any unreliability must be designed to fail safe instead of allowing an unintended arming. However, such fail safe design often results in warheads that fail to arm after firing.
To assure safe arming, conventional arming devices make use of separation sensors and timers. Unfortunately, these components add weight and volume which may significantly impact system design. Conventional arming devices also use on-board battery power as a source of electrical power for warhead arming. However, the loss of battery power results in a failure to arm.